Heating system



C. A. DUNHAM Y HEATING SYSTEM p'neys.

a She ets-Shee t 1 Filed Oct. 18,

Filed on. 1a, 1925 s Sheets-Sheet 2 Hi g C. A. DUNHAM HEATING SYSTEMFiled Oct. 18,

1923 8 Sheets-Sheet 3 vnems.

Dec. 4, 1934. c. A. DUNHAM HEATING 5151-1111 Filed 001. is, 192:5 aSheets- Sheet 4 2 v 3 y w w y w 4 7% j J 0 wr H W WW \1 W? m i 4 W1 1 C.A. DUNHAM HEATING SYSTEM Filed Oct. 18, 1923 8 Sheets-Shget 6 C. A.DUNHAM HEATINGVSYSTEM Dec. 4, 1934.

Filed Oct. 18; 1923 8 Sheets-Sheet 7 I}! W I C. A. DUNHAM HEATING SYSTEM1923 8 Sheets-Sheet 8 Filed Oc t. 18

Patented Dec. 4, 1934 HEATING SYSTEM Clayton A. Dunham, -Glencoe, Ill.,assignor to C. A. Dunham Company, Marshalltown,'lowa,

a corporation of Iowa Application October 18, '4': .Claims.

My invention relates to steam heating apparatus and its general purposeis to make certain improvements in this art conducive to more economicaloperation, more uniform distributionof the steam to the places more orless remote from the source of supply where the steam is condensed,better and more accurate automatic control of the apparatus forgenerating and distributing the steam, together with a wider rangeofadjustability for varying conditions of temperature than is possiblewith the steam heating systems here-' 1 tofore devised, and toaccomplish these results by certain devices and mechanisms which aresimple and inexpensive in their construction, positive and reliable inoperation, and which may be readily adapted for use, if need be, inconnection with existing installations.

More specifically, the objects of the invention comprisetheprovision ofa heating apparatus with certain new and improved constructions, devicesand expedients, preferably used in combination as shown in the drawingsbut susceptible of employment singly in some cases as will appearhereinafter, whereby-a constant but adjustable, that is a controlled,difierence in pressure may be maintained between the supply and returnpiping of the apparatus; whereby the condensate and air may be withdrawnfrom the radiators and the condensate returned to the boiler, eithercon.-

of water is accumulated; whereby a pumping whereby the quantities ofsteam received by the several radiators will be proportioned to theirrequirements regardless of the positions of the radiators with relationto the source of supply; whereby the system will be capable of variableoperation so that the pressure in the radiators may be kept either at orabove or below atmospheric pressure; and whereby the maximum quantity ofsteam that may be .introduced into the several radiators or heatingunits is subject to centralized control independent of conditionsexisting in the localities of the several radiators.

The invention consists in the new and improved constructions,arrangements and devices to be hereinafter described and claimed forcarrying out the above stated objects and such other incidental objectsas will be adverted to in the following description of the preferredembodiment of the invention shown in the ac- ,companying drawings.

In the drawings: v i Fig. 1 is adiagrammatic representation of thetinuously or intermittently as a certain volume 1923, Serial No. 669,363(Cl. 237-9) view of one of the radiator Fig. 3 is a side elevation ofthe mechanism for V withdrawing water and air from the return pipe ofthe radiating system.

Fig. 4 is a view, in elevation, of the same apparatus viewed from aplane at right angles to the plane of Fig. 3.

Fig. 5 is a sectional .view on line 5-5 of Fig. 3.

Fig. 6 is a longitudinal sectional view of the jet exhauster formingpart of the apparatus shown in Figs. 3 and 4. v r I Fig. "I is asectional view of the inlet pipe of one of the radiators and the valveassociated therewith.

Fig. 8 is a sectional elevation illustrating the difierential controllerfor maintaining constant difference of the pressure between the supplyand returnmains of the radiating system.

Fig. 9 is a sectional view on line 99 of Fig. 8.

Fig. 10 is a fragmentary view of the upper portion of the mechanismshown in Fig. 8 but with the parts in a different position,

Fig. 11 is a longitudinal sectional view of the device for venting thehurling water circuit of air.

Fig. 12 is a sectional view taken on line 1212 of Fig. 11.

Fig. 13 is a sectional view taken on line 1313 of Fig. 8...

Fig. 14 is'a fragmentary side elevation of the controlling mechanismshown in Figs. 8, 9,10 and 13.

Fig. 15 is a wiring diagram of the controller.

Fig. 16 is a fragmentary view, in elevation with parts in section, of adifferential gauge by means .ducer arranged in the steam supply main.

Fig. 21 is a sectional view on line 21-21 of. Fig. 20; and I Fig. 22 isa sectional view illustrating a modifled form of radiator inlet valve.

Referring first to Fig. 1, Adesignates a steam generator, B a steamsupply pipe leading from the boiler oi the generator for supplying steamto the radiating system consisting of a plurality of radiators', two ofwhich are shown and designated side of the building heated by theapparatus.

is a device subject to pressure in the boiler of the generator forcontrolling the operation of the generator through the closing andopening of one or more of the dampers. I is'a water tank at the end ofthe return pipe D and J a strainer arranged in the return pipe inadvance of thewater tank I.

The latter is provided with an outwardly opening check valve K. L is ahurling water pipe circuit one leg of which extends through withoutcommunicating with the water tank I. In the circuit L is arranged acentrifugal pump M .and a jet exhauster N which latter draws water fromthe tank I into the hurling circuit through a pipe 0 having a checkvalve P opening in the direction of the exhauster. The hurl'mg circuitalso contains a trap or device Q for ridding the hurling water of airdrawn into the same from the radiating system. The term air" is intendedto include any incondensable gas and is used in this sense in theappended" claims. R is a controlling device .for governing the motor S(Fig.- 15) which operates the pump M. The controller has a dualfunction. It operates to' start and stop the motor responsive topressure fluctuations in the supply and return pipes B and D so as tomaintain a constant but adjustable pressure differential as between themedium in these pipes. It also starts and stops the pump in accordancewith changes in the water level in the tank 1. Any suitable pumpingmechanism might be employed in place of that shown. Referring to Fig.15, T is-a source of supply of current for the pump motor S. U is acircuit "breaker operated through controlling mechanism R by a float intank, I, V a circuit breaker operatedthrough controller R. in accordancewith changes in the pressure differential in the supply and returnmains, and W a hand operated switch for putting the differential controlout of operation.

Again referring to Fig. 1, X designates the feed pipe of the boilerwhich is connected with the hurling circuit by a pipe Y and with thesupply pipe B by a pipe Z. V

Before describing in detail the construction of the severallnstrumentalitiesenumerated above, a brief summary will be given of theoperation of the system as a whole. -,In comparing the detail views ofthe apparatus shown in Figs. 3 and 4 with the general view of Fig. 1, itwill be observed that for the-purpose of general illustration of thewhole apparatus the controller R has been arranged in Fig. 1 to theright of tank I instead of back of it, as shown in Figs. 3 and 4.

Steam from the generator passes into. the supply main B and afterpassing the pressure reducer F enters radiator C throughpipe 25 and handoperatedvalve 26. interposed between valve 26 and the radiator is arestricted-inlet opening in the form of an-oriflce plate 2'1 (Fig. '7)which restricts the inflow of steam so thatmnd'er normal conditions ofoperation the maximum quantity so that all of the radiators regardlessof their position, receive substantially the same maximum quantity ofsteam (assuming radiators of equal volumetric contents), which quantitymay, of

course, be reduced by operation of the hand operated valves 26. Thesteam is retained in the radiator C by steam trap E which, however,permits outflow of water of condensation and air through pipe '29 to thecommon return pipe D.

I 30 designatesthe feed pipe for radiator C and 31 the outlet pipeleading to the common return pipe D. 32 and 33 indicate feed pipes.extending to other radiators, not shown, and 34, 35 the outlet pipesfrom these other radiators.

The pressure reducer F operates to throttle flow of steam through thesupply'pipe B in case of a rise of pressure in the boiler so that thepressure on the radiator side of the pressure reducer cannot exceed acertain maximum for which thepressure reducer is set. f The pressurereducer is also controlled by thermostat G so that if thetemperature inthe locality of the thermostat rises above a certain point, the steamsupply to the radiators is'throttled regardless of the pressure on thelow pressure side of the pressure reducer F. a

Water of condensation and air withdrawn from 'the radiating systempasses through pipe D and charged through the venting device Q which isconstructed so as to prevent the outflow of water. The excess of waterdrawn into the hurling circuit is forced from the same through pipe Yinto pipe X andthence into the boiler or generator A. Through pipe Z thepump and hurling water circuit are under boiler pressure. Pipe Y islocated preferably'at substantially the normal water level of theboiler.

The pump, therefore, serves two diating system which operates towithdraw from functions: It creates a vacuum in the return pipe of therathe radiating system the condensate and air therein; and it forces thecondensate back into the boiler so as to maintain the water therein at arelat vely constant level. v

The pump is subject normally to a dual control. Assuming that switch Wis closed any change'in pressure either in the supply main orin thereturn main which results in an increase in the difference in pressurein said pipes will operate the controller R to stop the pump and therebybring about a decrease of the suction on the return pipe until theproper balance is restored.

Referring to Fig. 15, with switch W closed by hand and switch V closedthrough balancing of pressures on the pressure responsive element orcontroller R, current will flow through the motor over the followingcircuit: Source of current supply T, wire 36, switch member 37, wire 38.

switch member 39; wire 40, pump motor 8,. wire 41, switch member42,.wire 43, switch member 44 and wire 45 to the source of currentsupply.

. By opening the switch W the differential control may be put out ofoperation but whether the diflerential control is operative or not thepump motor will be set in operation when the water intanklrisestoacertainlevelsothattheaccumulated condensate is always takencare of. With switch w closed the pump will be in operation either whennecessary to maintainproper difference in pressure between the supplyandreturn mains or when water has accumulated in tank I. with the floatcontrolled switch U closed the pump motor is supplied over the followingcircuit: battery T, wire 86, wire 46, switch member 47, wire 40, pumpmotor S, wire 41, switch member 48 and wire 49 to the battery.

The apparatus, the parts of which have bee enumerated above and theirgeneral relationship explained, will now be described in detail.

Steam traps of any suitable construction-may be used at the outlets ofthe radiators, Apreferred form of trap is shown'in-Fig. 2. 50 designatesa corrugated vessel containing an expansible fluid, the vessel beingprovided with a stud 51'which is screwed into a boss 52 in the uppersection 53 of a casing 54 having nipple 55-for attachment to theradiator. The thermostatic vessel 50 is provided on its under side witha valve 56 adapted to seat over a port 57-which leads to the radiatoroutlet pipe 29.

The radiator valve is shown in Fig. '1 and is preferably constructed asfollows: 58 is a valve casing having an inlet port 59- communicatingwith feed pipe 25 adapted to be closed by a valve 60 arranged on acorrugated structure 61, having 'a stem 62 provided on opposite sideswith notches 63 for non-rotatable engagement with a nut 64 which has athreaded engagement with an internal threaded sleeve 65 adapted to berotated by a handle 66, the sleeve and handle being supported on thebonnet 67 of the valve casing. The stem 62 is non-circular in crosssection and extends through .an opening of similar shape in a guideplate 68 which is interposed between the upper edge of the casing-andthebonnet. Consequently when the handle 66 is-turned nut 64 is forceddownwardly so as to seat the valve 60 over port 59. The outlet port ofthe valve casing is through 'a boss 69 secured by union 70 to a nipple71 which is screwed into the radiator C. The orifice plate 27 abovereferred to is arranged in the boss 69 and is held against a shoulder 72by a split ring 73. The oriflce plate is removable so that the valve foreach of the radiators may be fltted with a plate having an oriflce ofthe propersize to provide for the admission of the proper amountof'steam to the radiator dependent upon the position of the radiator withrespect to the source of supply of the other radiators of the system.

The pressure reducer F arranged'on' the supply pipe B is preferablyconstructed as follows (Figs. 20 and 21) 741sa valve casing interposedbetween sections of pipe B. Thecasing has an interior web 75 providedwith two .ports 76, 77 which. are adapted to be closed by a pair ofvalves 78, 79 on a stem 80 which passes'through a stu'fling box 80 inthe bonnet 82 of the valve casing. Valve stem '80 is secured to a yoke81 and the upper end of the yoke to -a stem 82v on a-plate 83 fastenedto the under side of a flexible diaphragm 84 arranged in the diaphragmcasing 86. The space-under the diaphragm 84 is open to the atmospherethrough an opening 86 in the bottom of casing 86. The space above thediaphragm 84 is connected by a pipe 87 with supply pipe B on the lowpressln-e side of the that is, the radiator side,-of the pressurereducer.

If the pressure on "this side of. the device exceeds that which isintended to be maintained, diaphragm 84 is deflected downwardly, againstthe action of the weight, moving valves 78, 79 against or toward theirseats so as to shut oil or diminish the inflow of steam through ports76, 77 until the balance shall have been restored.

The temperature controlled regulator comprises a motor means in the formof a flexible, corrugated vessel 94 which is secured by means of anupstanding threaded stem 95 and lock nut 96 to a cross piece 97 on theyoke structure 89.. The expansible vessel is provided on its under sidewith a boss 98 slotted to receive acircuiar pro- ;iection 99 on the endof a lever 100 pivoted to the yoke structure 89 and carrying anadjustable weight 101. The weight, therefore, tends to compress thevessel 94. Interposed between the threaded stem 95 and the flexibleportion of-the vessel is a boss 102 formed with a port 103 leading tothe interior of the vessel, which'port is connected by a tube 104 withthethermostat G which, as shown,consists of lower and upper headers 105,106 connected by tubes 107. Thermostat G contains a fluid which expandsand rise of temperature to the point at which the thermostat is designedto act, the pressure of the fluid in' the thermostat G, pipe 104 and'expansible vessel 94 overcomes the force exerted by weight 101, (whichforce will, of course, depend upon the position to which the weight hasbeen adjusted on lever 100) and moves the valves 78, 79 against ortoward their seats to shut 08 or throttle flow of steam to the sup plymainB. The arrangement is such, it will 5 be observed, that even thoughthe presure on the radiator side of the pressure reducer is insuflicientto deflect diaphragm 84 to close or throttie the ports of the pressurereducer, if the temperature is reached at which thermostat G is set tooperate, the thermostat will, nevertheless, bring about the closing orthrottling of the ports. The apparatus for exhausting the return main Dof the radiating system and introducing the condensate as feed waterinto the boiler of generator A is preferably constructed as follows;

The hurling water circuit L (Figs. 3, 4, 5 and 6) is composed of a pipe108 extending from top to bottom through the water tank I, a T 109 onthe top of the tank, a hollow fltting 110 which supports the tank (thelatter having a flanged neck 111 which rests upon the fitting 110), apipe section'll2, preferably provided with a shutoil valve 113,constituting the induction pipe of thecentrifugal pump M, a pipe section114 leading to the iet exhauster N (Fig. 6), a pipe section 115 leadingfrom the Jet exhauster to the vent trapQ, and a pipe section 116connecting the vent trap with the T 109. With the pump M in operationwater is driven centinuously through the hurling circuit as abovedescribed.

Water is drawn into the hurling circuit from 'exhausters.

cured to boss 128 by union 133 and to pipe section preferablyconstructed as follows: The jet nozzle of the. emustermomprises 'amember 117 secured by iunion ma toethe eduction pipe 114 of'pump Mandrtomiedwithav contracted throat at 119 and: with adiverging-passageway 120. A casing 121-=--is"secured to the enlarged end122 of jet member, 117 by means of a union 123, pipe 0 being. tappedinto the side of this casing. Pro-'- jecting. through the casing is anozzle member 124.having a threaded end 125 screwed into the end ofnozzle member 117.- The bore of nozzle member 124 ispreferably ofuniform diameter. The receiving tube of the jet exhauster is composed oftwo members 126, 127 having a tight fit one with the other, member'126having a threaded connection with a boss 128- on casing 121.- The throatof member 12615 flared as indicated at 129, the main portion of the bore130 being of uniform diameter. The passageway 131 through member 127 isof gradually increasing cross sectional area as is common with jet132'is an enclosing pipe section se- 115 by union 134. The water of thehurling circuit will ordinarily be quite hot and as a result, if a jetexhauster of ordinary construction were used diminution in kineticenergy of the jet would result from the tendency of the warm water toexpand in throat 129.

stead of the one shown there would be less contraction of the jetissuing from nozzle member 124 than with cold water. By the constructionshown the expansion is controlled in member 117 so that the heatreleased as a result of the pressure'change within the nozzle isutilized to increase the kinetic energy of the water particles as aresult of the expansive action and when the water issues 'from thestraight portion of the nozzle, that is member 124, it comes in acoherent stream which passes across the suction space in casing 121 andenters the flared portion of member 126 as a homogeneous jet.

The venting trap Q for ridding the water of the hurling circuit ofentrained air is preferably constructed as follows (Figs. 11 and 12):135 is .a casing provided at one end with, a separately formed closureplate 136 secured to the body of the casing by bolts 137. Secured to theinside of the cover plate is a casting 138 provided with a forkedbracket 139 to which is pivoted at 140 the arm 141 of a float 142.Casting 138 is formed with a port 143 in alignment with an opening 144in the cover plate in which port is arranged a valve 145 having a stem146 passing through a bushing 147 supported by a web 148 on casting'138. The float arm 141 has a finger 149, with a forked projection 150straddling the valve stem 146 and bearing upon .the valve 145 on oneside and a collar 151 on the other. An accumulation of water in casing135 will cause float 142 to close the port 143, thereby preventing theoutflow of water through the vent. Under ordinary conditions the waterlevel in casing 135 will be held low enough by the air trapped in theupper portion of tank Q so that valve 145 is unseated at intervals topermit the escape of Pipe section 115, as above shown as tapped into aboss 152 on one end of the casing. Preferably the casing is formed withan interior baflle web 153 arranged in front of That is. with warm waterand an ordinary nozzle in use inthe was inlet. Pipe 11s leads from thelowe part of the casing to the T 109.

Excess of water in the hurling circuit is forced from the T 109 throughpipes Y and X into the boiler below the. normal water level therein. The

hurling circuit operates under' boiler pressurewhich is balanced onopposite sides of pump M so that fluctuations in the pressure of steamin.

the boiler do not affect the operation of the pump. Moreover, theboilerpressure does not tend to backup the water in thevent trap Q.

The motor which intermittently drives pump M is controlledthroughchanges in the level of the water accumulated in tank I by thefloat controlled mechanism preferably constructed as follows (Figs. 4,5, 8, l3 and 14): 154 is afloat in the tank I arranged on an arm 155which issecured to a shaft 156 within the tank extension 157 on a'plate158 secured to the side of the tank I, the lever passing through anopening 159 in the plate 158. The shaft 156 is journaled in a stufilngbox 156 in the wall cftank extension 157 and in a bracket arm 156 onplate 158. A crank am 155 on the outer portion of shaft 156 is connectedby a link 160 with a trip 161 which latter is pivoted at 162 to the sideof a casing 163 which is supported on a shelf 164 projecting outwardlyfrom' plate 158. On

pivot stud 162 is mounted a weight 165 adapted to .be moved back andforth between stops 166, 167. The weight is provided with a pair ofstuds 168, 169 adapted to be engaged by the trip 161. The weight 165 isprovided with a stud 170 which projects through a slot 171 in the sidewall 172 of casing 163 (Fig. 8) and through a slot 173 in a rockingmember 174 which is pivoted at 175 to'the side wall 172 of the casing.The rocking member 174 is provided with a cross. bar 176 on which isarranged, with the interposition of suitable insulation 177, a pair ofcontact shoes 47, 48 (diagrammatically shown in Fig. 15). The

contact shoes 47, 48 are provided with extensions 178 connected byconductors 179 to binding posts 180. The line wires 46, 49 (Fig. 15) areconnected with the binding posts 180. The shoes '47,, 48 are adapted tobear against a pair of contacts 181 supported on inclined ledges 182 onthe upper ends of standards 183 mounted on an insulating block 184 inthe casing. On the standards 183 are binding posts 185' to which areconnected the pump motor leads 40 and 41. The

contacts 181 are held in placeon the standards by means of guide studs186 flxed to the ledges 182 and extending loosely-through the contactsand through an upper pair of contacts 187 (for the diflerential control)and by set screws 188 extending through the upper and lower contacts andinto the ledges 182, coiled springs 189 bein interposed between theupper and lower contacts of each pair. .With this arrangement a yieldingpressure is exerted between the contact shoes 47, 48 and contacts 181,and also between the coacting pairs of contacts forthe diflerential Icontrol to be hereinafter described.

Operation of the float control-when the level of the water in tank Ifalls, the float lever 155 is rocked raising link 160 and bringing trip161 against stud 168 on the tilting weight 165. The weight is thus swungfrom right toleft (Fig. 4) until it passes center, whereupon it falls tothe 'left until stopped by the bumper or stop member 167. This fallingmovement of the weight brings stud 170 .(Fig. 8) against the right handend of slot 173 in the rocking switch'member 174 rocking the switchmember to the right so as to separate contact shoes 47, 48 from thecooperating pair of contact 181 by a quick snap movement.

With the contact shoes 47, 48 bearing against the contacts 181 the pumpleads 40, 41 are con-' nected with the line wires 46,49 as indicated bythe diagram (Fig. 15). When this circuit is broken as above described,the pump motor is stopped unless it is receiving current over thecircuit controlled by .the pressure differential of the radiating systemis preferably constructed as follows (Figs. 4, 8, 9-, 10, 13 and 14):190 is a diaphragm casing supported on the bracket plate 158 on the sideof tank I (Fig. 4). The casing contains a flexible diaphragm 191 underwhich is arranged a spring 191 to which is secured a rod 192 (Fig. 8)extending through a.

I stumng box 193 and attached to a yoke 194, the

upper end of which carries a rod 195.- A lever 196 is pivoted at 197 toa standard 198 on the diaphragm casing and extends through yoke 194having a knife edge bearing 199 on which the lever fulcrums. The lever196 carries a weight, 200. Flxedfto rod 195 is a collar201having acurved arm 202 provided with a forked end 203 connected to a bell crank206 pivoted at 207 to the casing 163, the bell crank extending into thecasing through a slot 208 in the side thereof. A second bell crank 209is pivoted to a bracket 210 in the casing and to the upper end of theupstanding arm 211 of this bell crank is secured a cross bar 212carrying contact shoes'39, 42 (diagrammatically shown in Fig. 15) whichare adapted to bear against the pair of contacts 187 previouslydescribed. The other arm 213 of the bell crank projects out through theslot 208 in the side wall of the casing and has a forked portion 214with rounded edges engaging a collar 215 slidably arranged on rod 195between a coiled spring 216 held against a washer 217 positioned by nut218 6n the upper end of the rod, and a longer coiled spring 219 bearingagainst a washer 220 positioned against the fixed collar 201. Theupstanding arm 221 of bell crank 206 has a hook 222 which is adapted toextend over a lug 223 on the am 213 of bell crank 209. The lowercompartment of the diaphragm casing 190 is connected by a pipe 224 withthe pressure side of the system at someconvenient point, the pipe beingshown as extending into the fitting 110 which forms part of the hurlingcircuit. The upper compartment of the diaphragm casing 190 is connectedwith the vacuum'side of the apparatus by a pipe 225 which is shown astapped into the tank I.

Line wires 38, 43 are connected with binding, posts 226. (Fig. 13.) Fromthese binding posts extend a pair of wires 227to the binding posts 228on the contact shoes 39, 42, wires 22'! being guided by a cross member229 on the bell crank 211. In order to insure proper electricalconnection between the standards, 183 and the contacts 181 and 187 wires230 and 231 are provided which extend to these'contacts respectively,from binding posts 232 on the standards.

Operation of the diflerential controL-The differential control is putinto or out of operative connection with the apparatus by closing oropening hand operated switch W (Fig-15). Solon! as the difference inpressure between the supply and return mains is less than that which theapparatus is'inte'nded to maintain the contact shoes controlled switch Uis opened or closed. If the balance of pressures on diaphragm 191 isdisturbed either by increase of pressure under the same 'to increase thepressurediflerential over that for which the controller is set, thediaphragm is deflected upwardly against the action of weight 200,the-position of which on lever arm 196 determines the pressurediil'erential sought to be maintained. The upward movement of rod '195rocks the bell crank 208 but without disturbing the position of hellcrank 209 so long as the hook 222 bears upon the lug 223 on bell crank209. During this initial upward movement of'rod 195 spring 219. iscompressed. The spring 219 is in fact comdiaphragm or by diminution ofpressure above the pressed to a certain extent when the parts are in theintermediate position shown in Fig. 8. As

soon as the upward movement of the rod releases the hook 222 from thelug 223 bell crank 209 is given a sudden' rocking movement by the forceof spring 219 which moves the contact shoes 39, p

42 away from contacts 187 with a snapaction preventing arcing. The sprin219 which is compressed more than spring 218 gives sleeve .215- amovement of greater amplitude than the vertical movement of rod 195 toeffect a sumciently wide separation of the contacts as shown in Fig. 10.

"The pump motor circuitgoverned by the differential controllingmechanism is now broken v and the motor stopped, unless there is anexcess of water in tank I, in which case the pump will tion of the floatcontrolled switch U. Fig. 15

continue to operate because of the closed posishows the position of thedifl'erential controller in the circuit breaking position of its parts.

When the balanceof pressures on diaphragm 191 is restored rod 195 ismoved 'back to its normal position. During the flrst part of thismovement hook 222 passes under lug 223 keeping the contacts in theirseparated positions and compressing spring 216.- When the hook clearsthe lug bell crank 209 is given a quick movement through action ofspring 216 which moves the contact shoes 39, 42 against contacts 187closing the circuit. The pump M and exhauster N are" designed so as tobe capable of withdrawing from the radiating-system a larger quantity ofcondensate than will be formed under any normal conditions. Therefore ifthe, difference in-pres- I sure between the supply and return mainsbecomes less than the intended differential, resulting in a downwarddeflection of diaphragm 191 the pump will continue its operation for aproportionately longer period of time, namely until the diaphragm hasbeen deflected past center and to its upper or circuit breaking positioThe apparatus .is preferably provided with a gauge by which thedifference in pressure between the supply and return portions of thesystem my be ascertained. In the preferred arrangement shown (Figs. 4and 16 to 19 inclusive) the gauge is connected with the pressure side ofthe differential control diaphragm casing 190 and with the pipe whichconnects the vacuum sidev of the differential casing with tankI.

The differential gauge is preferably constructed as follows: 233 is acasing connected by pipe 234 with pipe 225. 235 is a casing connectedthe gauge tubes.

by pipe 236 with the lower side of the diaphragm casing 190. Thesecasings are supported on a plate 237 having ears 238 for attachment tothe side of tank 1. Within the casings are a pair of corrugatedmembranous flexible structures 239, 240 open at the bottom to pipes 234and 236. Supported in stuffing boxes 241,242 on the tops of the casingsand in recesses in the cross member 243 on the plate 237 are a pair ofglass gauge tubes 244, 245. The casings are filled with-bodies of liquidwhich rise to a greater or less extent in The base plate 237 is formedwith a groove 246 to receive a sliding member 247 on which is fastened ascale plate 248 provided with graduations indicating pressure units,ounces of pressure, for example, and fractions thereof, beginning atzero atthe bottom of the plate. The liquid column 249 in gauge glass 244will rise to a level determined by the pressure on the vacuum side ofthe apparatus while the liquid column 250 in gauge glass 245 will riseto a level determined by the pressure on the pressure side of theapparatus. By setting the gauge plate with the zero graduation in linewith the upper surface of the liquid column 249 a reading may be takenof the height of the liquid column 250 which will indicate thedifference of pressure maintained by the apparatus. In order tofrictionally hold the scale plate at the desired elevation the slide 247isv provided with elastic clips 251 which bear against ribs 252 on theback of the base plate 227. v The controlling device H for the generatormay be of any usual type. It is shown as consisting of a diaphragmcasing 253 (Fig. 1) the diaphragm of which operates on a lever 254pivoted to the diaphragm casing at 255 and connected by achain 256 withthe front damper 257 of the generator. There may also be a chainconnected to the furnace pipe damper.

In Fig. 22 I have shown a radiator inlet valve which may be used inplace of the radiator inlet valve shown in detail in Fig. 7. The purposeof both valves is the same, to provide means whereby the amounts of'steam which the radiators receive will be proportionedto theirrespective condensing capacities. In the arrangement of Fig. 7 this isaccomplished by providing the valves of the severalradiators of thesystem with barrier or oriflce plates having orifices properlyproportioned, with reference to the position of the ra-- diators in thesystem, to produce the desired results. In the arrangement shown in Fig.22

the position of the valve body controlling the inlet port is made todepend uponthe difierencev in pressureas between the supply pipe and thinterior of the radiator.

Pressure reducing radiator valve'.-Referring to Fig. 22, a pressurereducing valve is connected with the radiator inlet pipe 25 and withradiator C, the: means for making the latter connection being thoseshown in Fig. 7, namely, a nipple 71 screwed into the radiator and aunion 70 connecting this nipple with a boss on the valve casing. Thevalve casing consists of upper and lower members 256, 259, the bossengaged by union 70 being designated 260. Clamped between casing members258 and 259 is a flexible diaphragm 281. The lower casing member has aninlet port 262 in which is arranged a valve seat 263, A

provided with a stem 265 secured to a button 266 I to which diaphragm261 is fastened. A flexible corrugated'structure 267 is secured at itslower end to the valve body 264 and at its upper end against a web 263by means of a cap 269, A carvupon web 273 above referred to. Steam fromthe radiator supply pipe 25 can by-pass the valve 263 through duct 278so as to reach the under side of diaphragm 261. The chamber 279 abovethe diaphragm is .connected with the interior of the radiator C by apipe 280. Stem member 271 projects into a bonnet 281 on the valvecasing. This bonnet is internally threaded to receive the threadedportion 282 of the end of an operating 'stem 283 which projects throughthe bonnet and is provided with a hand grip 284. The valve body 264 maybe seated on valve seat 263 by turning hand grip 284, but when the valveis not seated in this positive way its position with respect to thevalve seat will depend upon the balance of steam pressures on oppositesides of diaphragm 261 and upon the pressure of spring 277 whichv may bevaried by adjustment of nut 275. When the pressure builds up in theradiator to a certain point diaphragm 261 will be deflected downwardlyso as to close the inlet port into the radiator or throttle it. When thepressure falls in the radiator the'diaphragm will be raised so as toincrease the eil'ective sizeof the inlet port of the radiator. j

Summary of operation of the. system as a whole-Steam from the boiler ofgenerator A passes through common supply pipe B and into the severalradiators through oriflce plates 27 having openings of different sizesproportioned,

with respect to the locations of the radiators in the system and theircondensing capacities, so that the quantity of steam entering eachradiator will'be proportioned to the heat demand upon that particularradiator (Fig. 7). A similar result is obtained by providing theradiators with the pressure reducing valves as shown in Fig. 22. Thesteam is retained in the radiators by steam traps E, E when operatingconditions are such that the radiators are completely fllled with steambut air and water of condensation are withdrawn through common returnpipeD by the vacuum created in the water tank I through operation ofpump M and jet exhauster N. The excess of water drawn'into the hurlingcircuit L ratus is out of operation, through the opening of switch W,and the system is functioning by gravity at pressuresslightly aboveatmospheric'pressures. The valve closes inwardly when the tank is undervacuum through operation of the pump. Whenever the water in tank Ireaches a certain' level, the float 154 closes a circuit throughpressure in the tank when the. exhausting appathe motor whereupon thepump is started and withdraws water from the tank forcing the same intothe boiler of the generator. If the water level in the tank I fallsbelow a certain point the pump isstopped provided the motor circuitisnot closed by operation of the pressure differential controller. Thepressure differential controller may be made effective or ineffectivethrough the closing or opening of circuit break'erW. With the'circuitbreaker W closed-the" differential conthe pressure of the hurling watercircuit, which is subject to boiler pressure, and the lower pressureexisting in tank I which corresponds to that in the return pipe D. Thesetwo controls are independent of each other. Eitheronewill keep the pumpmotor in operation regardlessof the other when conditions require theevacuation of water from tank I or the maintenance of a desired vacuumin the return pipe of the radiating system. Check valve P prevents waterfrom being forced by boiler pressure into tank I when thepump is,stopped. Such back flow of water, un-' less checked, might eventuallyfill the tank and set the pump in operation.

The maintenance of aconstant, but'adjustable,

difference in pressure between the supply and reapparatus. Thecondensate from the radiating turn mains of the radiating system hasseveral advantages: The introduction-oi steam. into each of theradiators of the system is assured. The amount of steam introduced intothe radiators is made dependent solely upon the pressure of steam in thesupply pipe and the size of the orifices leading to the severalradiators. By properlyproportioning the inlet orifices of the radiatorsand by providing the pressure reducer Fin the supply pipe, the maximumamounts of steam received by each radiator (subject to diminution bymanual valves 26) will be the same and can be accurately controlled froma central point. Through proper adjustment of the pressurereducer andwith properly proportioned radiator orifices, the apparatus can beoperated so as to maintain pressures in the radiators either at, aboveor below atmospheric pressure. This adjustment of pressure in theradiatorsof the system may be eil'ected automatically through operationof the thermostat G. For example, as-

suming thermostat G to be located outside of the building, its operationcan be controlled (variably by adjustment of weight 101) so that in warmweather for example, the thermostat will cause valves 16, 77 to throttlethe steam supply tothe radiators to such an extent that with the pumpirioperation under the diilerential control, atmos-' pheric or evensub-atmospheric pressure can be maintained in the radiators. Under mildweather conditions the supply of steam may be so reduced that theradiators will be only partially filled with steam; and this conditionwill necessarily result. with continued reduction of steam supply, afterthe maximum vacuum has been obtained. As the outside temperature fallsmore steam will be admitted to the radiators, and this inay be enough,for example, in very cold weather, to raise the pressure to atmosphericpressure or to a pointabove atmospheric pressure. The automatic controlof the pump by the controlling mechanism R. results in a more uniformcontrol of the supply of steam to the radiators. because the pressurediflerential is between the return and supply ends of the system insteadof being between the return piping and the atmosphere; and also resultsin an economy of electric current since the pump motor 8 is in operationonly when necessary tomaintain the desired conditions. The diii'erentialcontroller maintains a constant pressure diiferential as between theheating medium in the source of supply of heat, pipe B on the boilerside of the reducing valve 1', and the return pipins. which differentialis sulllcient to keep the radiators filled with steam and purged of airdifferential between and condensate under the severest weather condiqtions. The pressure reducing valve F under con-.

trol of the thermostat (3 reduces. to a greater or less extent, thepressure of steam going to the radiators; the pressure in the supplymain 3 on the. radiator side of valve I being regulated by thermostat Gso as to supply ,theradlators with the quantity of steam required-byexisting. heat demands. The operationof the diil'erential controller inconjunction with that of the pressure reducer F maintains as betweenradiators andretum piping pressure differentials which are of lessmagnitude than that between the source of supply and the return pipingand which :are 'proportioned to the quantities of heating medium whichmust be handled-by the system, these diff fe'rentials being less whenthe amount of steam I circulated is less and greater when the amount ofsteam circulated -is greater. This results in further economy in theoperation of the in full lines in Fig. 15) will ordinarily be open. Thediil'erential controller is, therefore, cut out of operation. The. pumpis operated under the control of the float controlled operator 154 (Fig..5) to return water. accumulated in'tank I at suitable intervals to theboiler.

Under these conditions the system will operate at pressures aboveatmospheric pressure. The

pump operates only at intervals and, therefore; does not maintain aconstant vacuum in the re-- turn piping. If for nighttime operation alower temperature is desired the weight 101 is'shifted to reset thevalves 76, 77 to positions closer to their seats. Thereafter thethermostat G operates as before' to vary the position of these valvesaccording to temperature changes, wherebythe desired lowerinside'temperature is maintained.

The traps will function as in daytime operation. But with the systemoperating at pressures above atmospheric pressure, check valve K on thetank I will open to permit the outflowof non-condensable gases. Theradiators'may beeither completely or only partially filled with steamaccording to the quantity of steam supplied to the radiators throughoperation of controller F,

This application is a continuation in part of my copending applicationSerial No. 518,386, filed November 28,1921. 1

I claim: y 1. In heating apparatus, the combination of a generator, aradiating system, supply and return- .pipes, a water tank, a hurlingwater circuit under boiler pressure comprising a pump and jet ex-.hauster for withdrawi'ng medium from the return pipe and introducingcondensate into the generator, and means for starting and stopping theoperationof the pump ln'response to a decrease or increase,respectively, inthe pressure the tank and hurling water circuit. A

2. In heating apparatus, the combination of a generator, a radiatingsystem, supply and return pipes, a water tank, a hurling water circuitunder boiler pressure comprising a pump and jet ex- 105 For nighttimeoperation the switch W (as shown 3. In heating apparatus, thecombination 01' a generator, a radiating system, supply and returnpipes, a water tank, a hurling water circuit under a boilerpressurecomprising a pump and jet exhauster for withdrawing medium Iro'mthe return pipe and introducing condensate into the generator, meanssubject to changes in the water level in the tank for controlling theoperation of the pump, means subjected to pressures in the tank andhurling water circuit for controlling the operation of the pump, andmeans for starting and stopping the operation of the pump in re-'s'ponse to a decrease or increase, respectively, in the pressuredifferential between the tank and hurling water circuit.

4. In an automatically regulated heating system, the combination ofheating units each having a restricted inlet opening so proportionedthat the quantity of heat carrying medium admitted to the unit can beregulated by variations in pressure in theheat carrying medium, apressure regulator for varying the pressure in the heat carrying medium,and a temperature controlled rcgulator'ior automatically controllingsaid pressure regulator. v

5. In combination in a heating system, a plurality of radiators, acommon supply main ,for supplying heating fluid to said radiators, eachradiator being connected to the supply main through a regulable butnormally fixed orifice to control the rate or flow to the respectiveradiators for a given pressure in the supplymain, and

' means-responsive to temperature to regulate the pressure of theheating fluid in said mains.

6. In a heating system, the combination oif a supply main for heatingfluid, aplurality oi radiators having connection withsaid main throughorifices for controlling the relative flow of heating fluid to eachradiator, a pressure regulator in the supply main for maintaining agiven pressure of the heating fluid supplied to said orifices, and

means responsive to temperature for controlling 'the setting or saidregulator. I

7. In a heating system, a radiator having a fixed orifice to control theinlet of heating fluid thereto, a supply main for heating fluid to besupplied to said orifice, a pressure regulator for holding apredetermined pressure upon said ori- I lice, and temperature responsivemeans for controlling the setting of said regulator so that the rate offlow of heating fluid through the orifice to the radiator is adjustedtothe requirements (or heat to be given ofl by the radiator..

8. In a heating system, the combination or ra-. diators each having arestricted inlet opening so proportioned that the quantity of heatcarrying medium admitted thereto can be regulated by variations in thepressure of the heat'carrying medium, an automatic pressure regulatorfor varying the pressure of the heat carrying medium, adjustment varyingmeans for varying the adjustment of saidautomatic pressure regulator,

and temperature controlled means governing said adjustment varyingvmeans. I

9. In a steam heating system, the combination of radiators each having arestricted inlet opening so proportioned that the. quantity of steamadmitted thereto can be regulated by variations in the pressure of theheat carrying medium, an automatic regulator for varying the pressureoi! the steam, and means for automatically varying the setting of thepressure regulator commensurate with. variations of temperature.

10. In a heating system, the combination of radiators each having arestricted inlet opening so proportioned that the quantity of heatcarrying medium admitted thereto can be regulated I by variations in thepressure of the heat carrying medium, an automatic pressure regulatorfor controlling'the pressure in the heat carrying medium, regulablemeans for varying the setting of the pressure regulator, and temperaturecontrolled means governing such regulable means whereby it mayautomatically vary the setting of the pressure regulator commensuratewith variations in temperature.

11. In a heating system for a building, the combination of a pluralityof radiators therein each having a restricted inlet opening soproportioned that the quantity of heat carrying medium admitted theretocan be regulated by variations in the pressure thereof, an automaticregulator for varying the pressure 01 the heat carrying medium,adjustment varying means for varying the adjustment of said pressureregulator, and thermalh sensitive means exposed to variations inpressure of the heat carrying medium, an automatic pressure regulatorfor varying the pressure of the heat carrying medium, regulable meansfor varying the setting of the pressure regulator, and

temperature controlled means governing said re g- I ulable means wherebyit may automatically vary the setting of the pressure regulatorcommensurate with variations in the atmospheric conditions external tothe building.

13. In a heating system, the combination of heating units having each arestricted inle't opening so proportioned thatthe quantity of heat vcarrying medium admitted thereto can be regulated byvariations in thepressure oi. theheat carrying medium, a pressure regulatorvior varyingthe pressure of the heat carrying medium,

means for loading said regulator to a variable degree comprising motormeans and a temperature controlled device for governing the action oi!said motor means.

14. In -a heating system, the combination of radiators each. having arestricted inlet openingso proportioned that'the quantity of heatcarrying medium admitted thereto can be regulated by variations in thepressure of the heat carrying medium, an automatic pressure regulatorloaded to a variable degree Ior varying the pressure of the heatcarrying medium, means for loading said regulator to a variable degreecomprising motor means and a temperature controlled device for governingthe action of said motor means.

15. In a heating system for a building, the combination of heating unitseach having a restricted inlet opening so proportioned that the quantityof heat carrying medium admitted thereto can be regulated by variationsin the pressure oi! the heat carrying medium, a loaded diaphragmpressure regulating valve for automatically regulating the pressure oi!the heat'carcharging condensate from said receiver; a ditdensate iromthe radiators and return piping ierential controller for the exhaustingapparatus for maintaining a controlled diiierential between thepressures in the supply and returnpiping; and a second controller forthe exhausting apparatus which operates in response to differences inwater level in the receiver, said exhaustingr apparatus being started byoperation of either controller but stopped only when both controllers Iare in their stopping positions.

17. In a steam heating system, the combination with a source oi steamsupply, a plurality of radiators, 'andsupply'and return piping: or areceiver for water of condensation; an exhausting apparatus iorwithdrawing air and coriand condensate from said receiver; adiflerential'controller for the exhausting apparatus for maintaining acontrolled diilerential between the pressures in the supply and returnpiping; a second controller for the exhausting apparatus which operatesin response to diflerv ences in water level in the receiver,-saidexhausting apparatus being started by operation of either controller butstopped only when both controllers are in their stopping positions; andmeans whereby the diiierential controller may be put out of operationand the second controller put into iullcontrol oi the exhaustingapparatus.

18. In a steam heating system, the combination with a source of steam uply. a plurality oi" radiators, and'supply and return piping; or areceiver i'orwater oicondensation; an exhaust-v in'g apparatus forwithdrawing air and condensate irom the radiators and return piping anddischarging condensate (mm the receiver;- acontroller. actuated by steampressures in the system for controlling the exhausting apparatus; and asecond controller for the exhausting apparatus operating, in response tochanges in 'water' level in said receiver, said exhausting apparatusbeing started by operation at either controller but stopped only whenboth controllers are in their stopping positions. I T

19. In a steam heating system, the combination with a source or steamsupply, a plurality oi radiators. and supply and return piping; or areceiver for water of condensation: and exhaust-. ing apparatus forwithdrawing air and controlleractuatedbysteampree'suresin-thetor-controlling the exhausting apparatus: a sec.- 'ond controller forthe exhausting apparatus operinresponseitochangesinwaterlevelinsaid atimreceiver, saidexhaustingapparatus beingstarted 'byoperation oieithercontroller butstoppedonly when both controllers arein theirstopping-peeltions; andmeanswherebythepressure actuated controller maybeput out of operation and the and supply and return piping: 01' areceiver for -'condensate connected with the return piping;

both controllers are in their stopping positions.

21. In a steam heating system, the combination with a source of steamsupply, a plurality oi radiators, and supply and return piping: of areceiver for condensate; an exhausting apparatus for withdrawing air andcondensate from the ra-- diators and return piping and dischargingcondensate iromthe receiver; controlling means'ior said exhaustingapparatu'sresponsive to changes 01' liquid level in the receiver andalso to changes in pressure differential between the supply and returnpiping so that the exhausting apparatus will be set in operation wheneither the liquid in the receiver reaches a certain level or when saidpressure diflerential falls below a predetermined minimum. and willcontinue to operate until both the desired liquid level and the desiredpressure diiierential have been reestablished.

22. In a steam heating system,-the combination with a source of steamsupply. a plurality of. radiators. and supply and return piping: ot areceiver for condensate; an exhausting apparatus for withdrawing air andcondensate irom the radiators and return piping and dischargingcondensate from the receiver; controlling means for said exhaustingapparatus responsive to changes of liquid level in the. receiver andalso to changes in pressure diiferential between the supply and returnpiping so that the exhausting apparatus will be set in operation wheneither the liquid in the receiver reaches a certain level or when saidpressure difl'erential falls below ,a predetermined minimum, and willcontinue to operate until both the desired liquid level and the desiredpressure diii'erential have been re-established; and means for renderingthe pressure control of the exhausting apparatus ineilective and makingthe exhausting apparatus subject only to control by changes in liquidlevel. I

23. In a steam heating system, the combinationwith a source of steamsupply. a plurality of radiators. and supply and return piping: of:steam traps at the outlets oi said radiators; means comprising anexhausting mechanism for maintain.- ing a controlled diiierentialbetweenthe'pressures in the supply and return piping, means comprising a valveactuated by pressure in the supply piping for controlling the flow ofsteam to the radiators, and a thermostat acting on said valve in a manac; to meet varying heat requirements oi the sys- 24. In a steam heatingsystem, the combination with ssource oi steam supply. a plurality oiradiators, and supply and return piping: 0! means for restricting theflow of steam into the radiators in proportion to their individualheatrequirements; means actuated by pressures in the supply and returnpiping for maintaining a con-' trolled diflerential between thepressures in the supply'and return piping and means for varyingsaiddiil'crentialinamannertomeettheheat requirementsotthesystemasawhole.

25. In a steam heating system, the combination with a source of steamsupply, a plurality oi radiators, and supply and return piping: oforifice plates, theoriflces oi which are proportioned so as to restrictthe flow of steam into the radiators .actuated by pressures in thesupply and return piping for maintaining a substantially constantpressure differential between the source of steam supply and returnpipin and controlling means in the supply piping for maintainingdeterminable pressure diflerentials, of less magnitude than that betweensupply and return piping, between the pressures in the radiators andreturn piping.

27. In a steam heating system, the combination with a source oi steamsupply, a-plurality of radiators, and supply and return piping: oi!means actuated by pressures in the supply and return piping formaintaining a substantially constant pressure diiierential between thesource of steam supply and the return piping; and thermostaticallycontrolled means in the supply piping for maintaining determinablepressure diflferentials, of less magnitude than that between supply andreturn piping. between the pressures in the radiators and return piping.

28. In a steam heating system, the combination with a source of steamsupply, a plurality oi radiators, and supply and return piping: of meansactuated by pressures in the supply and return piping for maintaining asubstantially constant pressure difl'erential between the source ofsteam supply and the return piping and controlling means for determiningthe pressure of steam supplied to the radiators in response to the heatrequirements of the system.

29. In a steam heating system, the combination with a source of steamsupply, a plurality of tween the pressures in the radiators and return'radiators, and supply and return piping: of means actuated by pressuresin the supply and return piping for maintaining a substantiallyconstant,

pressure diil'erential between the source of steam supply and the returnpiping and a thermostatically controlled means for maintainingdeterminable pressure diflerentials, of less magnitude than that betweensupply and return P pin be- 30. In a steam heating system, thecombination with a source or steam supply, a plurality oi radiators, andsupply and return piping: of means for maintaining controllablepressures in the source of steam supply; means actuated by pressures inthe supply and return piping for maintaining a substantially constantpressure dinerential between the source oi steam supply and the returnPiping: and controlling means in the supply piping for maintainingdeterminable pressure difierentials, of lessmagnltuiie than that betweensupply and return piping, between the pressures in the radiators andreturn piping.

31. In a steam heating system, the combination- I with a soin-ce ofsteam supply, a plurality oi radiators, and supply and return piping; ofmeans for retaining steam in the radiators while permitting the system.

the outflow of air and condensate therefrom; means actuated by pressuresin the supply and return piping, comprising an exhausting mechanism, formaintaining a substantially constant pressure difl'erential between thesource 01' supply and the return piping; and controlling means in thesupply piping for maintaining determinable pressure diil'erentials, 0!less magnitude than that between supply and return piping, between thepressures in the radiators and return piping. I

32. In a steam heating system, the combination with a source of steamsupply, a plurality oi radiators, and supply. and return piping: 01'means for retaining steam in the radiators while permitting the outflowof air and condensate therefrom; means actuated by pressures in thesupply and return piping comprising an exhausting mechanism, formaintaining a substantially constant pressure difierential between thesource of supply andthe return piping; and controlling means formaintaining determinable pressure differentials,

means actuated by pressures in the supply and return piping, comprisingan exhausting mechanism, for maintaining a substantially constantpressure'difierenti'al between the source of .supply and the returnpiping; and thermostatically controlled means in the supply piping formaintaining determinable pressure differentials, of less magnitude thanthat between supply and return piping, between the pressures in theradiators and return piping.

34. In a steam heating system, the combination with a source of steamsupply, a plurality of radiators, and supply and return piping: of meansactuated. by supply and return pipe pressures for maintaining acontrolled diii'erential between the pressures in the supply and returnpiping means 0 including a valve between the source oi supply and theradiators influenced by pressure in the supply piping for retarding to agreater or less extent the flow oi steam between the-source of supplyand the radiators; and thermostatic means sub- 'iect to temperaturesexternal .to the system, (or additionally controlling the flow of steamto the radiators inaccordance with the heat requirements oi the system.i

35. In a steam heating system, the combination with a source of steamsupply, a plurality of radia tors, and supply and return piping: ofmeans for maintaining a substantially constant pressure in the source oisteam supply; means-actuated by supply and return pipe pressures formaintaining a controlled diflerential between the press'ures in thesupply and return pipin means including a valve between the source 01supply and radiators influenced by pressure in the supply piping forretarding, to a greater or less extent-the the radiators, andthermostatic means for additionally controlling the flow 01' steamto theradiators in accordance with the heat requirements of 45 e 1 36. Inasteam heating system, the combination with a source of steam supply. aplurality oi radiators, and supply and return piping: of means actuatedby supply and return pipe pressures for maintaining a controlleddiilerential between the 15 1,oss,21a

pressure'in the supply and return piping; a thermostaticallyoperatedivalve mechanism in the supply piping between the source orsteam supply and the radiators and influenced by pressure in the supplypipingwhich is capable of closing to shut of! steam supply to theradiators or being opened to agreater or less extent, for additionallysive means controlling the exhausting apparatus.

to maintain a controlled diflere'ntial between the pressures in thesource and return piping; and a pressure reducer in the supply pipingfor determining the quantities of steam supplied to and the pressuresmaintainedin the radiate regardless oi fluctuations of pressure in thesource of steam supply, in accordance with the heat requirements of thesystem.

38. In a steam heating system, the combination with a source oi. steamsupply, a plurality oi radiators, and supply and return piping: oi meansfor maintaining steam in the radiators while permitting the outflow ofair and condensate; an exhausting apparatus for withdrawing fluids fromsaid radiators and return piping; pressure responsive means controllingthe exhaustingapparatus to maintain a controlled difl'erential betweenthe 85 pressures in the source and return piping; a pres-;

tion of a source of steam supply; a plurality of radiators having flxedrestricted inlet orifices of such sizes that the radiators. receivequantities of steam proportioned to their individual heat requirements;supply and return pipin thermostatic means for controlling the pressureof steam in the supply piping adjacent the radiator inlets in accordancewith the heat'requirements .oi .the system as a whole; and meanscooperating with the thermostatic means for maintaining a controlleddiirerential between the pressures in the supply and'return piping.

40. In a steam heating system, the combine. tion of a source of steamsupply; a plurality o! radiators having flxed restricted inlet oriflceso! m such sises that'the radiators receive quantities of steamproportioned to their individual heat requirements, and being providedat their outlets with steam traps; supply and return piping;thermostatic means i'or controlling the pressure or steam in the supplypiping adjacent the. radiator inlets in accordance with the heatrequirements of the system as a whole; and means cooperating with thethermostatic means and comprising an exhausting apparatus formaintaining a controlled diflerential between the pre'sj sures in thesupply and return piping.

41. he steam heating system-the combinationofasouroeoi'steamsupplyiaplwalityof radiators having iixed ctedinlet oriflces of such'sises that the radiators receive quantities'provided at their inlets with oriflce plates, the orifices 01' whichare proportioned so that the return PM.

of steam proportioned to their individual heat requirements; supply andreturn piping; thermostatic means, subject to temperatures external tothe system, for controlling the pressure oi! steam in the supply pipingadjacent the radiator inlets in accordance with the heat requirements ofthe system as a whole; and means cooperating with' the thermostaticmeans tor maintaining a con trolled differential between the pressuresin the supply and return piping.

42. In a steam heating system, the combination oi a source of steamsupply; a plurality of radiators having flxed restricted inlet orificesof .such' sizes that the radiators receive quantities of steamproportioned to their individual heat requirements; supply and returnpiping; thermostatic means, subject to temperatures external. to thespace being heated, for controlling the pressure of steam in the supplypiping adjacent the radiator inlets in accordance with the heatrequirements 01' the system as a whole; and means cooperating with thethermostatic means .tor maintaining a controlled diiierential betweenthe pressures in the supply and return piping.

, 43. In .a steam heating system, the combination of a source oi! steamsupply; a plurality of radiators having flxed restricted inlet oriflcesof such sizes that the radiators receive quantities of steamproportioned to their individual heat requirements, and provided attheir outlets with steam traps; supply and return piping; thermostaticmeans subject to temperatures external to the system for controlling thepressure of steam in the supply piping adjacent the radiator inlets inaccordance with the heat requirements 0! the system as a whole; andmeans cooperating with the thermostatic means and comprising anexhausting apparatus, for maintaining a controlled 'diflerential betweenthe pressures in the supply and return piping. 1

44. In a steam heating system, the combination of a steam generator; aplurality of radiators provided at their inlets with orifice plates, theorifices of which are proportioned so that the radiators receive steamin proportion to their individual heat requirements; steam traps at theoutlets of said radiators; supply and return piping; an exhaustingapparatus for withdrawing air and condensate from the radiators andreturn piping; a pressure reducer in the supply piping whichmaintainsdeterminate pressures in the radiator inlets regardless oi fluctuationsin generator pressure; and a controller for the exhausting apparatuscooperating with the pressure reducer tor maintaining a controlleddiiierential between the pressures in the supply and radiators receivesteam in proportion to their individual heat requirements: steam trapsat the outlets of said radiators; supply and return piping: anexhausting apparatus for withdrawing air and condensate irom theradiators and return piping; a pressure reducer in the supply pipingwhich maintains determinate pressures at the radiator inlets regardlessof fluctuations in generator pressure; and a thermostat-to control saidpressure reducer. and a controller tor the exhausting apparatuscooperating with the pressure reducer for maintaining a controlledditferentialbetweenthepressuresinthemppiy and Patent No. 1,983,218.,

pipes, heating units, each having a restricted inlet opening soproportioned that the quantity oi! heat carrying medium admitted to theunit can be regulated by variations'in pressure in the heat carryingmedium, a pressure regulator tor varying the pressure in the heatcarrying medium, a, temperature controlled regulator for automaticallycontrolling said pressure regulator,

and exhausting means for maintaining a lower pressure in the return pipethan in the supply pipe. 1

47. In an automatically regulated steam heating system, the combinationof supply and return pipes, radiators each having a restricted inletopening so that the quantity of heat carrying medium admittedto the unitcan be regulated by variations in pressure in the heat carrying medium,and each provided at its outlet with a steam trap to prevent the escapeof steam while permitting the discharge of water of condensation andair, a pressure regulator for varying the pressure in the heat carryingmedium, a temperature controlled regulator for automatically controllingsaid pressure regulator, and an exhausting means for maintaining a lowerpressure in the return pipe than in the supply pipe.

ICLAY'IOIN 'A. DUNHAM.

CERTIFICATE or connection.

CLAYTON A. DUNHAM.

is hereby certified that error appearsin the printed specification oithe above numbered patent requiring correction as follows: Page 8, lines17,, i8 and 19, claim 3, strike out the words and comma "means subjectedto pressures in the tank and hurling water circuit for controlling theoperation of the pump, and'line 23, of said claim, after "circuit"insert the words and means forpreventing the escape of steam from theradiating system while permitting the outflow of water and air'therelrom and that the said Letters-Patent shouldbe read with thesecorrections therein-that the same may conform to the record oi. the

.case in the Patent Oiiice.

Signed and sealed this 12th dayol February, A. D. 1935.

A (S eal) Leslie Frazer Acting Commissioner of Patents.

" December 4, 1934.

